ul li{
    list-style: none;
}
.aa{opacity: 0.9;
    width: 93%;
    height: 60px;
    background-color: black;
    margin: 0px;
    position: absolute;
    margin-left: 7%;
}
.aa ul li{
    float: right;
    margin-right: 50px;
    margin-top: 20px;
    padding-left: relative;
    color: white;
}
.aa ul li ul{
    width:100px;
    height:160px;
    margin-left: -50px;
    background-color:black;
    display:none;
    position: relative;
    text-align: center;
}
.aa ul li:hover ul{
    display: block;
    position: absolute;
}
.header{
    margin: 0px;
    padding: 0px;
}
* {
    margin: 0;
}
.header-logo img {
    float: left;
    width: 100%;
    height: auto;
    position: relative;
}
.header-logo p{
    position: absolute;
    top:0px;
    left:0px;
    color: white;
}
.a{
    float: left;
    font-size: 30px;
    opacity: 0.9;
}
.banner p img{
    margin: 40px 0px 10px auto;
    box-shadow: 3px 3px 3px;
}
.tubiao ul li{
    color:white;
    margin-right: 200px;
    margin-top:30px;
    float:left;
    display: block ;
}
.picture p img{
    box-shadow: 3px 3px 3px;         
}
main{
    width:93%;
    margin-left: 7%;
}


    .aa ul li a {
    text-decoration: none;
    color: white;
}
.aa a:hover{
    background-color: #666;
}
.picture p{
    color: white
    ;
}
.banner p{
    color:white;
}
footer{
    background-color: black;text-align: center;margin-top: 50px;opacity: 0.9;margin-bottom: 50px;
    font-size: large;
}
